Mody Pumps MS 121 - Manual (Page 7)

SEAL PROBE SENSOR OPTION
ALL MODY SEWAGE SUBMERSIBLES (MS RANGE) INCORPORATE A MOISTURE SENSOR
IN THE SEAL HOUSING. A PROBE INSULATED FROM THE PUMP BODY IS INSTALLED
IN THIS CHAMBER AND IS ENERGIZED USING A 12V SUPPLY FROM A RELAY LIKE
THE ABB LLC4.
IN THE EVENT OF LOWER SEAL WEAR THE PUMPED FLUID ENTERS THE SEAL
HOUSING CONTAMINATING THE OIL AND CHANGING THE ELECTRICAL RESISTANCE OF
THE FLUID. THE RELAY WILL IMMEDIATELY ENERGIZE SENDING A SIGNAL LIKE AN
ALARM IF EQUIPPED WHICH SHUTS DOWN OR WARNS THE OPERATOR OF OUTER SEAL
WEAR.
DO NOT IN ANY EVENT CONNECT THE THERMAL WIRES AND THE SEAL PROBE WIRE
IN SERIES. THE THERMALS AND OUTPUT FROM THE RELAY CAN BE CONNECTED TO A
SINGLE COIL IN THE CONTACTOR IN THE EVENT PUMP SHUTOFF IS REQUIRED
EITHER FOR OVERHEATING OR SEAL WEAR.
A COMPLETE SCHEMATIC IS ENCLOSED.